1. Field of the Invention
The present invention relates to a jig used for holding and fixing a part material during manufacturing of a part, or holding a part during inspection thereof, and in particular to such a jig that is generally used for a plurality of types of parts.
2. Description of the Prior Art
In manufacturing plants, jigs are used for holding part materials during assembling or welding of the parts, fixing for example.
When an exhaust pipe for an automobile is assembled by connecting two pipes to front and rear ends of a muffler by welding, for example, a jig is used for holding the pipes and the muffler in predetermined positions. In such a jig, clamps for holding appropriate portions of the muffler and the pipes are fixed to a base, so that the muffler and the pipes are positioned relative to each other according to a certain design.
To ensure sufficient high rigidity for supporting considerably heavy part materials, and avoid distortion during welding, the jig itself has a large weight, e.g., about 20 kg when it is used for a small-sized exhaust pipe.
In the case of exhaust pipes for automobiles, in particular, numerous different types of exhaust pipes are manufactured depending upon the types and versions of automobiles. In the real situation, jigs used in the manufacture of the exhaust pipes are specialized for respective types of products. Namely, a particular jig is used exclusively for each type of exhaust pipe. Thus, there has been a conventional problem that jigs having large weights must be handled each time the type of exhaust pipes manufactured on an assembly line is changed to another type, and heavy work is required for setting up the jigs.
Also, jigs used in the manufacture of products need to be stored for several years after shutting down the production line, for the purpose of production of spare parts. With an increase in the number of jigs stored, the storage space is increased, and increased time and labor are required for putting the jigs into and taking them out of the storage space. This has been a major problem in management of plants.
Similar problems concerning the known jigs are encountered in the case of jigs used for assembling other parts or inspecting those parts.